Firebat

iTrader: (7)

Its been 100 degrees outside for a week or 2 now. The deal is I burned up a fuel pump in under a month and my new fuel pump started whining/stalling just after 50 miles of highway driving. I have a little pressure come out the tank when I take the cap off.. It hasn't been near as bad since I replaced(and now bypassed) the black valve by the charcoal canister. However, I was surprised when I removed the hose from the hardline that goes to the charcoal canister and no pressure was released, yet if I remove the gas cap with that line off then I still have pressure come out of the cap.

Is there a valve on the sending unit assembly(inside the tank) on the hard line that goes to the charcoal canister? Shouldn't have there been air pressure released on that line? I didn't even smell gas from the disconnected line. Is the line just plugged? This is on a '92 V6.

Blazer79

If your tank is like mine, there are 4 lines coming from the tank:

1) The high pressure output from the pump.
2) The low pressure return from the injectors
3) A short line that ends near the left side tire.
4) A line that goes unobstructed to the charcoal canister.

I don't think that having little pressure in the tank when you remove the cap has anything to do with the fact that your pumps are going bad. Maybe there's debris on the bottom of the tank?

I had the problem that since my car sat for a very long time, the return line was clogged and impossible to clean even with a clotheshanger wire or with high pressure air.

If you drop your tank to change the pump again, make sure you can blow freely through the lines.

camaronewbie

All the EFI cars release pressure - it's the system. Carbed cars use vented caps, EFI cars do not, and thus the pressure release when removing the cap.